Backup full linux system to remotely mounted archival device (like a jump drive say)

Make a source directory like this on your destination jump drive:

/media/tim/ext4_ext/Chromebook_lubuntu18_finalbackup/
                         ^
                         |
                         +------ auto mount point for my jump drive

login to system to be backed up.

Type a command like this on the system being backed up.

$ sudo rsync -aHAXv / --exclude={"/bak1","/cdrom","/dev","/lost+found","/mnt","/proc","/run","/sys","/tmp"}  192.168.1.14:/media/tim/ext4_ext/Chromebook_lubuntu18_finalbackup

Note: you will need a passwordless ssh login credential setup for root access into the destination system.